Researchers divided nearly 800 teens, aged 14 to 18, into two groups based on their salt intake. Those in the high-intake group consumed an average of more than 4,100 milligrams (mg) of salt a day, while those in the low-intake group consumed an average of less than 2,400 mg a day.

Both groups consumed far more salt than the 1,500 mg per day maximum (about two-thirds of a teaspoon) recommended by the American Heart Association.

"Even in these relatively healthy young people, we can already see the effect of high [salt] intake, suggesting that high [salt] intake and obesity may act synergistically to accelerate cellular aging," said lead author Dr. Haidong Zhu, an assistant professor of pediatrics at the Medical College of Georgia, in Augusta.

The researchers examined how salt intake affects protective ends on chromosomes, known as telomeres. Telomeres naturally shorten with age, but telomere shortening is accelerated by smoking, physical inactivity and high levels of body fat.

Telomeres were much shorter in overweight and obese teens with high salt intake, but not in normal-weight teens with high salt intake, according to the study, which was presented at an American Heart Association meeting in San Francisco.

"Lowering [salt] intake, especially if you are overweight or obese, may slow down the cellular aging process that plays an important role in the development of heart disease," Zhu said in an association news release.

Reducing salt intake might be easier than losing weight for overweight young people who want to lower their risk of heart disease, Zhu said. Most salt in the diet comes from processed foods, so parents can help by cooking fresh meals more often and by offering fresh fruit rather than potato chips for a snack, she said.

Although the study found an association between eating salty foods and faster cellular aging, it did not necessarily prove a cause-and-effect relationship.

Data and conclusions presented at meetings typically are considered preliminary until published in a peer-reviewed medical journal.